Hi,
I have a 96 Seville STS. A couple of months ago I started to hear an audible hum. It only hums when I go over 40MPH and the wheel has to be straight up or left; when I turn a little bit to the right it instantly stops. When I bring the wheel back center it starts right back. I can feel it in the steering wheel and throttle pedal ever so slightly. I thought the tires (Michelins) needed rotating and balancing, but that didn't help. I thought maybe the power steering pump might be going but I'm not sure. I thought it might be power steering related because the hum is similar to what a car sounds like when the power steering fluid is low and you turn the wheel, but not as loud. What's throwing me is why it doesn't hum when I turn right, or, when I drop below 40MPH. Does anyone have a clue to what might be causing this? I prefer to take care of this myself if I can get some feedback. Thanks for the help. dv..

Hellloooo da324!! Pleeaassee check out this thread that I started regarding an issue I'm having with my '96 & tell me if this sounds like the same thing you're experiencing.

http://www.cadillacforums.com/forums/showthread.php?t=12625

I too am stumped on what is causing this. Recently I "zig-zagged" my car down the road going about 41-42 MPH & THINK that I MIGHT have noticed the sound going away when the car was moving right. Which would indicate that maybe the right wheel bearing is slowly beginning to go out, since the load is reduced when turning right. But I'm still not really convinced.

Overall, the car runs fine & the sound seems to fade away above 50-55 MPH, but I'm very disappointed that I can't figure it out.

Again, please read the entire post & replies & tell me what you think. Perhaps we can "bash our heads together" & figure this strange thing out.

Sorry to hear that your having the same problem, but also elated that it's not just mine. Now I think there could be hope in figuring it out. Two heads are always better than one.

Cheers,
96 STS

Wheel Hub Bearing. I had the same problem on my '98 STS in the right front wheel. The bearing was starting to go and I would get a humming noise when at higher speeds. It also went away when I turned in a certain direction or when the car went over a bump in the highway. For the brief period of time after the bump went the car is still moving upward, the preesure on the bearign would eb gone for a second and it would stop. As soon as the car settled back down it would come back. I would recommend taking it to the dealer just to make sure. That last thing you want is for it to overheat and sieze up on the highway.

Thanks for the replies. I think it might just be the wheel bearings as stated. How hard is that to change and how much does it cost? I read the post that was started and one post said wheel bearings could be the culprit. The only difference is that mine doesn't get louder when I turn the wheel to the left as that post suggests; it just stays the same. My 96 only has 77k so I don't think it is tranny related either as mine runs like a dream. Thanks again and PLEASE let me know whatever you discover. donnie

I had mine replaced becuase I didn't have the time myself (School). The Bearings in my car have an electronic ABS sensor in them. I'm not sure if they work the same in your car. If you decide to do it yourself, I would suggest using a factory service manual if you have access to one. Good Luck. :thumbsup:

Thanks Dan,
I'm trying to get a manual off of ebay right now, Do you remember how much it cost to have them replaced? Also, did you have it done at a dealership, or, a local service garage? Thanks again for your help, dv..

Your not gonna like this. My caddy dealer quoted me $1100 or so. I had it done by my trusty mechanic for about $700. The extended warranty I bought actually covered a few hundred of that. I don't remember how much though. I would get a quote from a dealer and then get a quote from a good mechanic. Ask them both what they charge for parts and labor and then decide.

I had..........Sounds like a "similiar problem".
As to the humming noise i cant be too sure. Was probably more concerned about the shimmy in the steering wheel and never noticed. Or there was no hum. But it does sound somewhat similiar so will post this just incase it can help.

Started getting a shimmy in the steereing wheel at low speeds. Steering wheel would start to shimmy round 50K (30mph). But would then stop around 60K (40mph).
Took it to the shop hopin that was maybe a balance problem. Asked them to do that, but also look for anything else that might be the culprit.
Balanced and rotated all tires. Was told that nothing else was seen that could be the problem. Paid my 80 bucks (had oil, lube and filter as well), and left hopin to be happy.
Drove the car home and it was smooth as glass. I was ecstatic !

But approx a week later started to feel the shimmy comeing back (at about 50K/30mph) but very slightly. And then progressed back to the same thing as before.

Asked about it in the forums and was suggested it may be a wheel bearing. Got more info on how to personally check bearings and what not and did that.

This Is The Info I Recieved:
"Jack the front of the car up so the front tires are off the ground.
Then (do this to each side) grab the bottom of the tire and pull in and out with a bit of force.
Also do this by grabbing the sides and pulling in and out as well.
If there is play when you do this, the bottom will tell you if the ball joint is bad, and the middle will tell you if your tie rods are bad. Also, if it moves no matter where you pull and push, suspect a wheel bearing.
You can crawl under and see if any linkages are loose or look for parts that are worn as well. You might get lucky and find it.
Other things to suspect is bent rim, bad CV joint, and worn strut, and maybe more if I've missed something."

What I Then Did And Found Was:
Raised one side and pulled hard on the tire and everything was solid as a rock.
Lowered that side and did the other side and got the same thing.
Then raised both sides and tried again. Seemed to get some flexing when I pulled the tires from the sides but felt that was just steering flexing. Didnt neccesarily get actual movement, was more like a very slight, tight springy kinda flexing. Nothing of any real sinificance.

Then removed the tires and checked all the boots and started pulling on all the rods and shafts.
What I discovered was that the upper part of the passenger side stabalizer link (where it joins to the bracket thats on the strut) would move in and out along the bolt when I pulled and pushed on it. Seemed that the bushing was shot. The other side did not do that.
Everything else appeared to be rock solid other than that one bushing.
Attempted to replace it myself but no hope in hell. Needed a torch and dont have one.
Took it back to my shop and had them do it. They assured me it had to be replaced but chances are it wouldnt correct the problem I was having. They were right.

Dont know if you have any of these same symptoms but these are some things I also noticed.Remember this is all at low speeds:

1) Shimmy in the steering wheel did not happen every single time I pulled from a stop and approached 50k. Have to say about 80% of the time.
2) Had been feeling like the whole car was bouncing at times. Not that often but every now and then. This was also at low speeds.
3) Also noticed by chance when looking at my hood ornament as I was pulling from a stop, that my whole front end appeard to be shifting (shimmying) to the left and right. That also seemed to correspond with the sensation of the whole vehicle bouncing. That happened before hitting 50k/30mph .
Not very frequently did that happened though.
The bouncing sensation and the whole front end shifting did not happen everytime before the steering wheel shimmy. That was something I noticed happening periodicly.
The steering wheel shimmy though was about 80% of the time when I pulled from a stop. Like Id already said
But should also add that not as bad and sometimes not at all if I pulled from a stop with some aggression.

Very SLIGHT vibration at high speeds but felt and saw it all at low speeds. (allignment appeared to be fine)

So to sum it all up:
Tire rods, Wheel bearings, Ball joints, Tire rotation, Balance, etc where basicly eliminated as being the problem. Didnt leave much else did it ?
Fortunatelly I go to a shop that doesnt change things on a whim just because the symptoms appear to point at a certain thing. They want to be positive. None of this "Looks like this so it will cost you $$$$$s".

They were as confused as I was. So the last thing they could think of before going back to square one were the actuall tires themselves.
Though they had plenty of tread. And balance was successfull. They were about 6 years old.
Put the car on the hoist, put it into drive, and lo and behold they were just a wavin.
Explained why after rotation it was ok for about a week.
The front tires belts were going. The rears were ok. But once putting the rears on the front, seein as there age, and the extra strain being on the front end, it took only a week for there belts to start going.

New tires and everything was back to norm.

Sorry for such a long post. But before dropin cash and replacing things because it appears to be this or that. Properly diagnose the problem.
The responses you recieve hear are suggestions to the symptoms you give. Its not written in stone. They are suggestions to what to look into.
Take those suggestions, then find out what is required to affirm or dismiss them.
Im fortunate enough to know of a shop that will not do a repair unless they are 100% sure that is the problem.
It is sad to say but I believe the majority are grasping at straws. If the symptoms refer to or resemble this then thats what to change. Its amazing how often they can be wrong. Though they can cover there asses by showing you the part and some kinda of wear to tell you it would fail soon.

Dont waste your money and change things till your positive.
And if you have someone else do it, tell them you want a 100% money back gaurantee (in writing) if it does not fix the problem your having.
Trust me.....You probably wont get it. :histeric:

Like I said. Dont jump in and start changing things just because someone says it sounds like or looks like. If I did that it would have cost me a fortune. Only to find out I needed new tires. Sure some of the symptoms were the same but ....
Dont spend anything untill you are assured and guaranteed that that is the problem. ;)

Murphyg made an excellent point about checking out all the possible cause before haveing anything fixed. I did the test where you jack up the wheel and grab it to see if it moves. In my case, as soon as Touched it, it moved. When I grabbed it, it had an unusual amount of play in all directions. This is what led me to take it to the dealer just to make sure. Hopefully your problem will be less serious, but but it's always good to check. Good Luck.

Murphyg made an excellent point about checking out all the possible cause before haveing anything fixed. I did the test where you jack up the wheel and grab it to see if it moves. In my case, as soon as Touched it, it moved. When I grabbed it, it had an unusual amount of play in all directions. This is what led me to take it to the dealer just to make sure. Hopefully your problem will be less serious, but but it's always good to check. Good Luck.

Exactly.
Was in the middle of righting my novel when you posted.
Thanx

Thanks for all the info. I guess it could be my tires although they are only 2 yrs old (Michelins). They were rotated and balanced yesterday to no avail. My next step is to put it on jacks and have a look. Oh, I never mentioned that the noise has gotten a little bit louder over the last few months, but still not too loud. Luckily it's not my primary ride; if I have to park it for awhile to figure it out I will. Thanks and keep the info coming as it is well apprectiated. dv...